Journal Article

Visualizing moiré ferroelectricity via plasmons and nano-photocurrent in graphene/twisted-WSe2 structures

Fu, Matthew, Halbertal, Dorri, Liu, Song, Zhu, Xiaoyang, Moore, S. L., Huang, Chun-Ying, Zheng, Wenjun, Schuck, P. J., Basov, D. N., Cobden, David H., Wang, Zhiying, Dean, C. R., Shao, Yinming, Liu, Mengkun, Hone, James C., Yang, Birui, Zhang, Shuai, Liu, Yang, Fonseca, Jordan, Pasupathy, A. N., Li, Baichang, Fogler, M. M., Handa, Taketo, Rossi, S. E., Pan, Tsai-Chun, Xiong, Lin, Sun, Zhiyuan, Xu, Xinyi, Jing, Ran, Chen, Xinzhong, Xu, Xiaodong

2023

Overview

Ferroelectricity, a spontaneous and reversible electric polarization, is found in certain classes of van der Waals (vdW) materials. The discovery of ferroelectricity in twisted vdW layers provides new opportunities to engineer spatially dependent electric and optical properties associated with the configuration of moiré superlattice domains and the network of domain walls. Here, we employ near-field infrared nano-imaging and nano-photocurrent measurements to study ferroelectricity in minimally twisted WSe 2 . The ferroelectric domains are visualized through the imaging of the plasmonic response in a graphene monolayer adjacent to the moiré WSe 2 bilayers. Specifically, we find that the ferroelectric polarization in moiré domains is imprinted on the plasmonic response of the graphene. Complementary nano-photocurrent measurements demonstrate that the optoelectronic properties of graphene are also modulated by the proximal ferroelectric domains. Our approach represents an alternative strategy for studying moiré ferroelectricity at native length scales and opens promising prospects for (opto)electronic devices. Recent experiments have shown the formation of ferroelectric domains in twisted van der Waals bilayers. Here, the authors report near-field infrared nano-imaging and nano-photocurrent measurements to investigate ferroelectricity in minimally twisted WSe 2 by visualizing the plasmonic and photo-thermoelectric response of an adjacent graphene monolayer.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 140/125 / 147/136 / 639/301/119/996 / 639/624/1107/527/2257 / 639/624/400/2797 / 639/766/400/1021 / Bilayers / Domain walls / Electric polarization / Electronic equipment / ENGINEERING / Ferroelectric domains / Ferroelectric materials / Ferroelectricity / Ferroelectrics and multiferroics / Graphene / Humanities and Social Sciences / Infrared imaging / Infrared spectroscopy / Monolayers / multidisciplinary / Nanophotonics and plasmonics / Near fields / Optical properties / Optoelectronics / Photoelectric effect / Photoelectric emission / Plasmonics / Plasmons / Polaritons / Polarization / Science / Science & Technology - Other Topics / Science (multidisciplinary) / Superlattices